A method of producing extracts is currently in use (patent RU 2232026 A61K35/78, V01D 11/02) by means of extraction of ground plant raw material under vacuum (up to −0.3 atm.) at 15-35° C. for 1-15 days, using structured water as the extractant.
The main disadvantage of this method is that the process of extraction is carried out in a laminar diffusion regime (infusion at a fixed bed of solid phase), in which a rapid saturation of an extractant layer near the solid particles with extractables takes place, which leads to a decrease in the concentration gradient during the saturation time and the fall effectiveness of the extraction process. In addition, the said method does not provide a sufficient overheating of the solvent in the material, which leads to a decrease in the yield of extractable substances. The disadvantage of this method is a significant process duration (1-15 days), which does not exclude the formation of various microorganisms, especially bacteria, molds, fungi, yeast and can lead to a souring of a mixture.
A method of extracting materials is currently in use (patent RU 2163827 V01D 11/02), including the crushing of raw materials, vacuum treatment, contacting with a solvent, heating of a mixture and extracting in a vacuum-impulsive mode. Prior contacting with components the solvent and raw materials are heated and degassed using a vacuum-impulsive treatment. The heating of the components and their mixtures is carried out to a temperature not causing the denaturation of the material. The extraction is carried out at a residual pressure of 0.1-13.3 kPa and at time to achieve it and relief—0.5-1.0 sec, temperature of 40-80° C. at the module (extractant:raw materials) which is equal to 10.
Said method of extraction has some disadvantages. Under the proposed modes of vacuum treatment the method does not provide a sufficiently complete extraction of components from the raw materials. Extraction of raw materials is carried out at high flow rate of extractant (module (extractant:raw materials) is equal to 10). Moreover, the extraction process is carried out at temperatures of 40-80° C., in consequence of which a destruction of a number of biologically active components takes place, which greatly reduces the quality of the extracts obtained.
Method of extraction of raw materials is currently in use (RU 2213606 B01D 11/02). The method includes the grinding and heating of raw materials, the degassing of raw materials and extractant, heating the solvent to a temperature by 5-15° C. below the temperature of heating of raw materials, at that the degassing of raw materials and extractant is carried out separately using impulsive-vacuum treatment including keeping the mixture during 3-5 minutes after each impulsive-vacuum treatment cycle. The extraction is carried out in vacuum-impulsive mode at 70° C. and residual pressure in the receiver of 1-10 mm. Hg.
An apparatus that realizes the said method of extraction is currently in use (patent RU 2213606 V01D 11/02) containing an extractant tank and extractor, which are interconnected and to a pipeline through the quick response valves, to a condensate receiving tank and receiver, a vacuum pump which is connected to a receiver, a reflux condenser which is installed above the extractor, providing a condensation of the vapor of the extractant, a heater and a pump providing heating and delivering of the heating liquid medium into the extractant tank and the extractor tank.
The said method of extraction and the apparatus possess some disadvantages. Under the proposed mode of vacuum treatment the method and apparatus do not provide a sufficiently complete extraction of components from the raw materials. Extraction of raw materials is carried out at high flow rate of extractant (module extractant:raw material is equal to 10). Moreover, the extraction processes are carried out at temperatures up to 70° C., in consequence of which a destruction of various biologically active components takes place, which greatly reduces the quality of the extracts obtained. The latter circumstance leads to the inapplicability of the method for obtaining high-quality pharmaceutical preparations of plant, animal raw materials and seafoods.
An apparatus for producing the extracts (inventor's certificate SU No V01D 850 108 11/00) which has a cylindrical body with a rotor, separated with the radial walls into chambers, equipped with hinged bottom doors and spray system with shut-off valves in the upper part of the solvent receiver, the device for loading and unloading of solid substances. The extractor is equipped with bars, which are installed including the ability of reciprocal motion, located on them turners, guide and lever connected to the Shut-off valve.
The disadvantage of this apparatus includes raised packing of solid mass on the surface of the bottom, while the reciprocating motion of agitator turners occurring, which increases the hydraulic resistance of the layer of a solid phase, reducing the velocity and quality of the extraction process. The disadvantage is also includes a structural complexity of the apparatus.
It should be noted, that at temperatures above 39° C. the fast and irreversible processes in materials often occurs, which do not lead directly to denaturation, however, adversely affecting the biological activity of the contained components. For example, some organic compounds may have a transition from one configuration to another one including the loss of biological activity.
No above methods are applicable for the extraction of easily oxidized substances.
The aim of the present invention is to develop a method for extracting of different types of biological raw materials and the apparatus for implementing this method, allowing to increase the yield of extractable substances and improve their quality due to the possibility of conducting the processes at lower temperatures, as well as preventing oxidative reactions in the material.